Techniques for dual modulation with light conversion

• US 10,133,120 B2
• Filed: 10/05/2017
• Issued: 11/20/2018
• Est. Priority Date: 08/21/2014
• Status: Active Grant

• Current Assignee: Dolby Laboratories Licensing Corporation (Dolby Laboratories Incorporated)
• Original Assignee: Dolby Laboratories Licensing Corporation (Dolby Laboratories Incorporated)
• Inventors: Wan, Chun Chi, Ninan, Ajit
• Primary Examiner(s): A, Minh D
• Application Number:
  US15/726,199
• Publication Number:
  US 20180031921A1
• Time in Patent Office: 411 Days
• CPC Class Codes: G02F 1/133601 for spatial active dimming
• CPC Class Codes: G02F 1/133609 including means for improving the color mixing, e.g. white
• CPC Class Codes: G02F 1/133614 using photoluminescence, e.g. phosphors illuminated by UV or blue light
• CPC Class Codes: G02F 2202/36 Micro- or nanomaterials
• CPC Class Codes: G09G 2320/0233 Improving the luminance or brightness uniformity across the screen
• CPC Class Codes: G09G 2320/0242 Compensation of deficiencies in the appearance of colours
• CPC Class Codes: G09G 2320/041 Temperature compensation
• CPC Class Codes: G09G 2320/0646 Modulation of illumination source brightness and image signal correlated to each other
• CPC Class Codes: G09G 3/3426 the different display panel areas being distributed in two dimensions, e.g. matrix

Abstract

Techniques for driving a dual modulation display include generating backlight drive signals to drive individually-controllable illumination sources. The illumination sources emit first light onto a light conversion layer. The light conversion layer converts the first light, such as blue or ultraviolet light, into second light, such as white light. The light conversion layer can include quantum dot materials. Liquid crystal display (LCD) modulation drive signals are generated to determine transmission of the second light through individual color subpixels of the display. These LCD modulation drive signals can be adjusted based on one or more light field simulations to account for non-uniform, spatial color shifts. Alternatively, one or more light field simulations based on a uniformity assumption determine intermediate LCD modulation drive signals. A compensation field simulation, using backlight drive signals, is then used to adjust the intermediate LCD modulation drive signal for color correction.

Claims

1. A method for driving a display comprising:

emitting first light by one or more illumination sources onto a quantum dot layer;

converting the first light into second light by the quantum dot layer;

determining intermediate display modulation drive signals by one or more light field simulations;

determining a compensation field for spatial color non-uniformity related to traveling distances of light from the one or more illumination sources; and

compensating for the spatial color non-uniformity by adjusting the intermediate display modulation drive signals.

2. The method of claim 1 wherein the traveling distances account for one or more reflections.

3. The method of claim 1 wherein the quantum dot layer is a single sheet.

4. The method of claim 1 wherein the quantum dot layer comprises a plurality of segments.

5. The method of claim 1 wherein the one or more illumination sources are individually controllable.

6. An apparatus comprising a processor and configured to perform the method recited in claim 1.